* eshell/esh-ext.el (eshell-external-command): Pass args to

* eshell/esh-ext.el (eshell-external-command): Pass args to
`eshell-find-interpreter'.
(eshell-find-interpreter): Add new second parameter ARGS.

* eshell/em-script.el (eshell-script-initialize): Add second arg
to the function added as MATCH to `eshell-interpreter-alist'

* eshell/em-dirs.el (eshell-dirs-initialize): Add second arg to
the function added as MATCH to `eshell-interpreter-alist'

* eshell/em-term.el (eshell-visual-subcommands): New defcustom.
(eshell-visual-options): New defcustom.
(eshell-escape-control-x): Adapt docstring.
(eshell-term-initialize): Test `eshell-visual-subcommands' and
`eshell-visual-options' in addition to `eshell-visual-commands'.
(eshell-exec-visual): Pass args to `eshell-find-interpreter'.